DE 102009033219 A1, which is incorporated by reference, shows a method and a device for determining a road profile of a traffic lane ahead of a vehicle. An image capture device or the vehicle's own motion data is used to determine a road height profile of the traffic lane ahead of the vehicle. Herein the image capture device can be a camera which is fixedly arranged in the front area of the vehicle and comprises two image recording units. Depending on the determined road height profile, an active chassis control or adaptive dampening system can be controlled.
Accident prevention is an increasingly important purpose of driver assistance systems. In particular emergency braking systems make a major contribution in this regard. Their effectiveness, however, depends very much on the coefficient of friction between the road surface and the tyre of the vehicle. In particular in wet conditions the coefficient of friction is much lower than that on a dry road.
WO 2011/007015 A1, which is incorporated by reference, shows a laser-based method for classifying coefficients of friction in motor vehicles. To this end, signals of a Lidar or CV sensor, which are directed towards the road surface, are evaluated and in particular the amplitude found in this way is used to determine a coefficient of friction for the measured road surface. For example it can be estimated whether the road surface is made of snow, asphalt or ice.
It has shown that state-of-the-art methods for determining the coefficient of friction involve drawbacks: additional Lidar sensors are expensive, the Lidar sensor in the vehicle must be specifically directed towards the road, and the coefficient of friction of the road cannot be estimated sufficiently in advance.